/* options for 8bit timer counter 0 (TCO) csbits */
#define OVERFLOW_TC0_OFF		0 // turn off TC0
#define OVERFLOW_TC0_16US		1 // TC0 overflows every 16 usec
#define OVERFLOW_TC0_128US		2 // TC0 overflows every 128 usec
#define OVERFLOW_TC0_1024US		3 // TC0 overflows every 1.024 msec
#define OVERFLOW_TC0_4096US		4 // TC0 overflows every 4.096 msec
#define OVERFLOW_TC0_16384US	5 // TC0 overflows every 16.384 msec

/* options for 16bit timer counter 1 (TC1) csbits */
#define OVERFLOW_TC1_OFF		0 // turn off TC0
#define OVERFLOW_TC1_4MS		1 // TC1 overflows every 4.0960 msec
#define OVERFLOW_TC1_33MS		2 // TC1 overflows every 32.768 msec
#define OVERFLOW_TC1_262MS		3 // TC1 overflows every 262.14 msec
#define OVERFLOW_TC1_1049MS		4 // TC1 overflows every 1.0486 sec
#define OVERFLOW_TC1_4194MS		5 // TC1 overflows every 4.1943 sec

/* options for 8bit timer counter 2 (TC2) csbits */
#define OVERFLOW_TC2_OFF		0 // turn off TC0
#define OVERFLOW_TC2_16US		1 // TC2 overflows every 16 usec
#define OVERFLOW_TC2_128US		2 // TC2 overflows every 128 usec
#define OVERFLOW_TC2_512US		3 // TC2 overflows every 512 usec
#define OVERFLOW_TC2_1024US		4 // TC2 overflows every 1.024 msec
#define OVERFLOW_TC2_2048US		5 // TC2 overflows every 2.028 msec
#define OVERFLOW_TC2_4096US		6 // TC2 overflows every 4.096 msec
#define OVERFLOW_TC2_16384US	7 // TC2 overflows every 16.384 msec

/* set click slection bits on timer counters to determin overflow freq */
#define timercounter0_setoverflow(overflowfreq) TCCR0B = ((TCCR0B & 0xf8) | (overflowfreq))
#define timercounter1_setoverflow(overflowfreq) TCCR1B = ((TCCR1B & 0xf8) | (overflowfreq))
#define timercounter2_setoverflow(overflowfreq) TCCR2B = ((TCCR2B & 0xf8) | (overflowfreq))
